<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        /*标签名选择器*/
        div{
            border: 1px red;
        }

    </style>



</head>
<body>

<div>div1</div>
<div>div2</div>
<div>div3</div>

<span>span1</span>
<span>span2</span>
<span>span3</span>

</body>
</html>